Johannesburg - Tiger Brands, Africa's second-biggest consumer foods maker, took a R849m ($82m) writedown on its loss-making Nigerian business on Thursday.
It struggles with tough competition and weak margins.
South Africa-based Tiger Brands, which also flagged as much as a 9% rise in first-half profit, has been trying to make money out of Dangote Flour Mills since paying $188m for about a 63% stake in the maker of flour and pasta two years ago.
But Dangote Flour Mills, which suffered a $17.4m quarterly loss in February, is struggling with tough competition that has forced it to heavily discount its products.
"The company continues to believe that Nigeria is central to its expansionary ambitions," Tiger Brands said in a statement.
Tiger Brands is expanding further into the rest of Africa to offset slow growth at home, where debt-laden consumers are cutting back on spending and a weaker rand currency pushes up input costs.
The company said first-half headline earnings per share - which excludes the write off - would increase by 5% to 9% as it grapples with high input costs and slowing consumer spending.